Heat radiator

ABSTRACT

A heat radiator for emitting infrared radiation to the human body has a heat source which is energized to emit infrared radiation, whose penetration depth into the human body is to near warmth sensing points of the human body, and an insulator for covering the surface of the heat source to be directed toward the human body. The free surface of the insulator forms a surface for contacting with the human body and the thickness of the insulator is less than the penetration depth of the infrared radiation into the insulator.

TECHNICAL FIELD

The present invention relates to a heat radiator which has a surface forcontacting with the human body.

BACKGROUND ART

A heating apparatus such as heating floor, heating toilet seat, etc. hasa surface for contacting with the human body. In conventional heatingapparatuses having a surface for contacting with the human body, a heatsource is energized to generate heat, the generated heat is transferredto an insulator covering the heat source, and the transferred heat isconducted to the surface of the insulator. Thus, the surface of theinsulator, which forms a surface for contacting with the human body, isheated to an appropriate temperature. However, the infrared radiationfrom the heat source cannot be directly absorbed by the human bodybecause it is completely absorbed by the insulator having largethickness.

A conventional heating apparatus, wherein the heat generated by a heatsource passes to the surface of an insulator through heat transfer andheat conduction, thereby heating the human body in contact with thesurface of the insulator, has a problem of not having quick heatingcapability because the speed of the heat passage through heat transferand heat conduction is slow and it takes a long time before the surfaceof the insulator is heated to an appropriate temperature.

DISCLOSURE OF INVENTION

An object of the present invention is to provide a heating apparatuswhich has a surface for contacting with the human body and is excellentin quick heating capability.

According to the present invention, there is provided a heat radiatorfor emitting infrared radiation to the human body, comprising a heatsource energized to emit infrared radiation, whose penetration depthinto the human body is to near warmth sensing points of the human body,and an insulator covering the surface of the heat source directed towardthe human body, wherein the free surface of the insulator forms asurface for contacting with the human body and the thickness of theinsulator is less than the penetration depth of the infrared radiationinto the insulator.

In the present heat radiator, the heat source is energized to generateheat and emit infrared radiation.

The heat generated by the heat source passes to the surface of theinsulator through heat transfer and heat conduction. The thickness ofthe insulator is less than the penetration depth of the infraredradiation into the insulator. As a result, the thickness of theinsulator is small. Thus, the heat generated by the heat source quicklypasses to the free surface of the insulator, thereby quickly heating thefree surface of the insulator which forms the surface for contactingwith the human body to an appropriate temperature.

Part of the infrared radiation from the heat source is absorbed by theinsulator and converted to heat. The infrared radiation is absorbed andconverted to heat at every depth point of the insulator because thethickness of the insulator is less than the penetration depth of theinfrared radiation into the insulator. The heat converted from theinfrared radiation passes to the free surface of the insulator throughheat conduction. The heat converted from the infrared radiation quicklypasses to the free surface of the insulator because the infraredradiation is absorbed and converted to heat at every depth point of theinsulator and the thickness of the insulator is small. Thus, the freesurface of the insulator which forms the surface for contacting with thehuman body is quickly heated to an appropriate temperature.

Part of the infrared radiation from the heat source passes completelythrough the insulator to the outside to be absorbed by the human body incontact with the free surface of the insulator because the thickness ofthe insulator is less than the penetration depth of the infraredradiation into the insulator. This infrared radiation is completelyabsorbed by the human body and converted to heat by the time it reachesthe vicinity of the warmth sensing points because the penetration depthof the infrared radiation into the human body is to near the warmthsensing points. Thus, the infrared radiation quickly heats the vicinityof the warmth sensing points to an appropriate temperature.

As is clear from the above description, the heat radiator in accordancewith the present invention can quickly heat the free surface of theinsulator, which forms the surface for contacting with the human body,to an appropriate temperature and also directly and quickly heat thevicinity of the warmth sensing points of the human body to anappropriate temperature. Thus, the heat radiator in accordance with thepresent invention has a high capability of quick heating. Thus, aheating apparatus into which the heat radiator in accordance with thepresent invention is incorporated has a high capability of quickheating.

The insulator is preferably made of a polyester resin such aspolypropylene, polyethylene terephthalate, polybutylene terephthalate,polyethylene naphthalate, etc., or styrene resin such as acrylonitrilestyrene, acrylonitrile butadiene styrene, etc. These resins have highertransmittance of infrared radiation than other resins. Thus, a majorpart of the infrared radiation from the heat source passes through aninsulator made of any one of these resins to directly heat the humanbody. Thus, the quick heating capability of the heat radiator is furtherenhanced. Polyethylene terephthalate is highly effective to enhance thequick heating capability of the heat radiator because polyethyleneterephthalate has high transmittance of long-wave infrared radiation,which is easily absorbed by the human body.

The insulator preferably adheres closely to the heat source. When theinsulator adheres closely to the heat source, the heat transfercoefficient between the heat source and the insulator increases and thequick heating capability of the heat radiator increases. Adherencebetween the heat source and the insulator is enhanced by the use of aheat generating sheet as the heat source.

The heat source is preferably a porous heat generating sheet. When aporous heat generating sheet is bonded to the insulator, adhesive agentinfiltrates into the pores of the heat generating sheet. Thus, theporous heat generating sheet adheres closely to the insulator. When aporous heat generating sheet is integrally molded with the insulator,resin material forming the insulator infiltrates into the pores of theheat generating sheet. Thus, the porous heat generating sheet adheresclosely to the insulator. Thus, the quick heating capability of the heatradiator increases.

The porous heat generating sheet is preferably a mixed paper of carbonfibers and natural pulp fibers. The carbon fibers are efficient infraredradiators. The mixed paper of carbon fibers and natural pulp fibers isporous and can endure exposure to a high temperature fused resin. Thus,the heat generating sheet made of mixed paper of carbon fibers andnatural pulp fibers is suitable for integral molding with an insulatormade of resin. The carbon fibers are preferably surrounded by voidspaces. The void spaces form heat insulating layers. Thus, thetemperature of carbon fibers surrounded by void spaces quickly risesafter the mixed paper is energized. Thus, carbon fibers quickly emitinfrared radiation after the mixed paper is energized. Thus, the quickheating capability of the heat radiator increases.

The void ratio of the mixed paper is preferably equal to or greater than60 volume % . When the void ratio of the mixed paper is equal to orgreater than 60 volume % air layers or heat insulating layers arereliably formed around the carbon fibers. Thus, the temperature risingspeed of the carbon fibers increases and the time from the start of theenergizing of the mixed paper to the start of the emission of theinfrared radiation decreases. Thus, the quick heating capability of theheat radiator increases.

The heat radiator may be provided with a infrared reflector facing thesurface of the heat source directed away from the human body. Theinfrared rays radiated away from the human body are reflected toward thehuman body, thereby contributing to temperature increase of the humanbody. Thus, the quick heating capability of the heat radiator increases.

According to the present invention, there is provided a heatingapparatus having a heat radiator as described above, the heatingapparatus comprising a front surface resin layer opposing the human bodyand a rear surface resin layer, wherein the front surface resin layerforms the insulator of the heat radiator covering the surface of theheat source directed toward the human body, and the front surface resinlayer and the rear surface resin layer cooperate to sandwich the heatsource of the heat radiator.

The thickness of the front surface resin layer is less than thepenetration depth of the infrared radiation into the front surface resinlayer. Thus, the front surface resin layer is thin and does not havesufficient strength against external forces. However, the front surfaceresin layer is reinforced by the rear surface resin layer when the frontsurface resin layer and the rear surface resin layer cooperate tosandwich the heat source. Thus, a heating apparatus which has a quickheating capability and sufficient strength against external forces canbe obtained.

The front surface resin layer and the rear surface resin layer must beunited into an integral body so as to reinforce the front surface resinlayer by the rear surface resin layer. The following processes arepreferable to unite them into an integral body.

{circle around (1)} A process comprising the steps of insertingprojections extending from the front surface resin layer and penetratingthrough the heat source into penetration holes formed in the rearsurface resin layer, and heat fusing the end portions of the projectionsto form swellings.

{circle around (2)} A process comprising a step of inserting projectionsextending from the front surface resin layer to penetrate through theheat source and being provided with swellings at their ends intopenetration holes formed in the rear surface resin layer.

In the process {circle around (1)} or {circle around (2)}, the frontsurface resin layer and the rear surface resin layer are mechanicallyunited. Thus, they can be reliably united into an integral body even ifthey are hard to bond together.

{circle around (3)} A process comprising the steps of abutting the frontsurface resin layer against the rear surface resin layer and energizingan electric wire embedded beforehand in the abutting surface of the rearsurface resin layer or the front surface resin layer to fuse and bondthe abutting surfaces.

In the process {circle around (3)}, since the bonded surface can beeasily re-fused by energizing the electric wire, the front surface resinlayer can be removed from the rear surface resin layer to enable removalof the heat source from the heating apparatus. Thus, reuse of the heatsource is expedited.

{circle around (4)} A process comprising the steps of placing the heatsource on the premolded front surface resin layer or the premolded rearsurface resin layer, placing the premolded front surface resin layercarrying the heat source or the premolded rear surface resin layercarrying the heat source in a mold for low pressure molding, pouringresin material of the rear surface resin layer or the front surfaceresin layer into the mold, and closing the mold to carry out lowpressure molding.

In the process {circle around (4)}, the unity between the front surfaceresin layer and the rear surface resin layer increases and the strengthof the heating apparatus against external forces increases. Quickheating capability of the heating apparatus increases because adherenceof the heat source to the front resin layer increases. Low pressuremolding protects the heat source from damage during the moldingoperation.

In the process {circle around (4)}, the premolded front surface resinlayer or the premolded rear surface resin layer may be provided withprojections for immobilizing the heat source. Thus, the heat source iskept from sliding during the molding operation. When a heat generatingsheet is used as the heat source, the heat generating sheet is kept fromsliding and crumpling.

In the process {circle around (4)}, the premolded rear surface resinlayer may be provided with irregularities or grooves in the surfacereceiving the heat source. Thus, the front surface resin layer intrudesinto the irregularities or grooves to be firmly united with the rearsurface resin layer as an integral body. Thus, the strength of theheating apparatus against external forces increases.

{circle around (5)} A process comprising the steps of molding the frontsurface resin layer or the rear surface resin layer, holding the moldedfront surface resin layer or the molded rear surface resin layer in themold, placing the heat source on the front surface resin layer or therear surface resin layer, pouring resin material of the rear surfaceresin layer or the front surface resin layer into the mold, and closingthe mold to carry out low pressure molding.

In the process {circle around (5)}, the same effects as in the process{circle around (4)} can be obtained. In the process {circle around (5)},the front surface resin layer, the heat source and the rear surfaceresin layer can be united into an integral body by a continuous seriesof processes. Thus, the trouble of transferring partially fabricateditems such as the premolded front surface resin layer, the premoldedrear surface resin layer, etc., and placing them in the mold can beavoided.

{circle around (6)} A process comprising the steps of vacuum attractinga resin film to a mold for low pressure molding, placing the heat sourceon the resin film, pouring resin material of the rear surface resinlayer into the mold, and closing the mold to carry out low pressuremolding.

In the process {circle around (6)}, the same effects as in the process{circle around (4)} can be obtained. In the process {circle around (6)},the distribution of the thickness of the front surface resin layer canbe made even and the the thickness of the front surface resin layer canbe made small. When the distribution of the thickness of the frontsurface resin layer is even, the temperature distribution of the freesurface of the front surface resin layer which forms the surface forcontacting with the human body is even. Thus, the comfort of the eatingapparatus is enhanced. When the thickness of the front surface resinlayer is small, the quantity of infrared radiation passing through thefront surface resin layer increases and the quick heating capability ofthe heating apparatus increases.

{circle around (7)} A process comprising the steps of placing the heatsource on a first mold for low pressure molding, pouring resin materialof the front surface resin layer or the rear surface resin layer intothe mold, closing the mold to carry out low pressure molding to unitethe front surface resin layer or the rear surface resin layer and theheat source into an integral body, placing the front surface resin layerunited with the heat source or the rear surface resin layer united withthe heat source in a second mold for low pressure molding, pouring resinmaterial of the rear surface resin layer or the front surface resinlayer into the mold, and closing the mold to carry out low pressuremolding.

In the process {circle around (7)}, unity between the front surfaceresin layer and the rear surface resin layer increases and the strengthof the heating apparatus against external forces increases. Quickheating capability of the heating apparatus increases because adherenceof the heat source to the front surface resin layer increases.

In the process {circle around (7)}, the first mold for low pressuremolding may be provided with projections for immobilizing the heatsource. Thus, the heat source is kept from sliding during the moldingoperation. When a heat generating sheet is used as the heat source, theheat generating sheet is kept from sliding and crumpling.

In the processes {circle around (1)} to {circle around (7)}, the heatsource may be given the same color as the front surface resin layer. Inthis case, the heat source cannot be seen through and users of theheating apparatus do not feel uneasy even if the front surface resinlayer is light colored.

In the processes {circle around (1)} to {circle around (1)}, the frontsurface resin layer and/or the rear surface resin layer may be foamedresin layers. Thus, the heating apparatus becomes flexible and thecomfort of the heating apparatus is enhanced.

In the processes {circle around (1)} to {circle around (7)}, the heatsource may be wrapped with a resin film beforehand. In this case, theheat source is protected from damage when the front surface resin layer,the heat source and the rear surface resin layer are united into anintegral body and the manufacturing efficiency of the heating apparatusincreases because handling of the heat source becomes easy.

When the heat source is wrapped with a resin film beforehand, theportion of the resin film opposing the rear surface resin layer may bean infrared radiation reflection film. In this case, the infraredradiation in the direction away from the human body is reflected towardthe human body by the infrared radiation reflection film, therebycontributing to the temperature increase of the human body. Thus, thequick heating capability of the heat radiator increases.

In any one of the processes {circle around (1)} to {circle around (3)},a cushioning layer may be sandwiched between the rear surface resinlayer and the heat source. When the front surface resin layer, the heatsource and the rear surface resin layer are united into an integral bodyby any one of the processes {circle around (1)} to {circle around (3)},there is a possibility of their not being sufficiently united into anintegral body because of size mismatch between the front surface resinlayer and the rear surface resin layer caused by manufacturing error.However, if a cushioning layer is sandwiched between the rear surfaceresin layer and the heat source, any size mismatch between the frontsurface resin layer and the rear surface resin layer is absorbed by thecushioning layer. Thus, sufficient unity can be obtained.

When a cushioning layer is sandwiched between the rear surface resinlayer and the heat source, the cushioning layer may be integrally moldedwith the rear surface resin layer. Thus, the trouble of inserting thecushioning layer between the front surface resin layer and the rearsurface resin layer can be avoided when the front surface resin layer,the heat source and the rear surface resin layer are united into anintegral body. Thus, the manufacturing efficiency of the heatingapparatus increases.

When a cushioning layer is sandwiched between the rear surface resinlayer and the heat source, the cushioning layer may be a heat insulator.In this case, the heat generated by the heat source is not absorbed bythe cushioning layer, the heating efficiency of the heat sourceincreases and the quick heating capability of the heating apparatusincreases.

In any one of the processes {circle around (1)} to {circle around (7)}the rear surface resin layer may be honeycombed. In this case, theweight of the heating apparatus is reduced.

In any one of the processes {circle around (1)} to {circle around (1)},the rear surface resin layer may be provided with a hollow wherein aheat sensor is received. In this case, the heat source can be preciselycontrolled and the heating apparatus can be precisely controlled.

If the temperature distribution of the heat source is uneven, the frontsurface resin layer facing the higher temperature portion of the heatsource may be made thick and the front surface resin layer facing thelower temperature portion of the heat source may be made thin. In thiscase, temperature distribution of the free surface of the front surfaceresin layer which forms the surface for contacting with the human bodybecomes even and the comfort of the heating apparatus is enhanced.

The heating apparatus in accordance with the present invention can beapplied as various kinds of heating apparatuses such as room heatingapparatuses, toilet heating apparatuses, etc. Examples of room heatingapparatuses are floor heating panels, wall heating panels, heatingcarpets, heating panels, etc. Examples of toilet heating apparatuses areheating toilet mats, heating panels, heating toilet seat covers, heatingtoilet seats, etc. The heating apparatus in accordance with the presentinvention wherein the heat source is flexible and the front surfaceresin layer and the rear surface resin layer are made of flexiblematerial can be applied to a heating robe, winter clothes, a chair seat,a chair backrest, a chair armrest, etc.

The room heating apparatus in accordance with the present invention mayfurther comprise a human body detecting apparatus which can detect thepresence of a person in a room and a heat source controller whichenergizes the heat source only when the human body detecting apparatusdetects the presence of a person. Thus, the electric power consumptionof the room heating apparatus is reduced because the room heatingapparatus operates only when a person is present in the room.

The toilet heating apparatus in accordance with the present inventionmay further comprise a heat source controller which energizes the heatsource in accordance with a control signal from outside the toilet.Thus, the toilet heating apparatus can be started just before a personenters the toilet and stopped just after the person leaves the toilet.Thus, the toilet can be comfortably used and the electric powerconsumption of the toilet heating apparatus can be reduced.

The toilet heating apparatus in accordance with the present inventionmay further comprise a heat source controller which energizes the heatsource only when an electric lamp in the toilet is switched on. In anordinary home, the toilet light is switched on only when the toilet isused. Thus, the above described heat source controller enablescomfortable use of the toilet as well as reduction of electric powerconsumption.

The toilet heating apparatus in accordance with the present inventionmay further comprise the human body detecting apparatus which can detectthe presence of a person in a toilet and a heat source controller whichenergizes the heat source only when the human body detecting apparatusdetects the presence of a person. Thus, the electric power consumptionof the toilet heating apparatus is reduced because the toilet heatingapparatus operates only when a person is present in the toilet.

In the toilet heating apparatus further comprising the human bodydetecting apparatus which can detect the presence of a person in atoilet and a heat source controller which energizes the heat source onlywhen the human body detecting apparatus detects the presence of aperson, the heat source controller can be adapted to energize the heatsource a predetermined time after the human body detecting apparatusdetects a person. The human body detecting apparatus detects a personjust after the person enters the toilet. Around 10 to 20 seconds passbetween the time a person enters the toilet and the time the person sitson the toilet seat. Thus, even if the heat source controller energizesthe heat source a predetermined time after the human body detectingapparatus detects the presence of a person, some time is still availablebetween the time the heat source is energized and the time the personsits on the toilet seat. The surface of the toilet heating apparatus forcontacting with the human body can be reliably heated to an appropriatetemperature during the available time because the toilet heatingapparatus in accordance with the present invention is excellent in quickheating capability. Thus, the electric power consumption of the toiletheating apparatus is reduced without impairing the comfort of the toiletheating apparatus owing to the delayed turnon of the toilet heatingapparatus.

In the toilet heating apparatus further comprising the human bodydetecting apparatus which can detect the presence of a person in thetoilet and a heat source controller which energizes the heat source onlywhen the human body detecting apparatus detects a person, the heatsource controller can be adapted to energize the heat source at time T-tafter the human body detecting apparatus detects a person, where T isthe time between detection of the person by the human body detectingapparatus and seating of the person on the toilet seat, and t is thetime from energizing of the heat source to the completion of the heatingof the front surface resin layer to a predetermined temperature. Bythis, the electric power consumption of the toilet heating apparatus isreduced without impairing the comfort of the toilet heating apparatusowing to the above-mentioned delayed turnon of the toilet heatingapparatus.

In the toilet heating apparatus further comprising the human bodydetecting apparatus which can detect the presence of a person in thetoilet and a heat source controller which energizes the heat source onlywhen the human body detecting apparatus detects a person, the human bodydetecting apparatus can be adapted to detect the distance between thehuman body detecting apparatus and the person, and the heat sourcecontroller can be adapted to energize the heat source when the distancebetween the human body detecting apparatus and the person becomes apredetermined value. In this case, if the human body detecting apparatusis located near the toilet seat, the toilet heating apparatus can bestarted when the person reaches a point a predetermined distance fromthe toilet seat. In this case, the electric power consumption of thetoilet heating apparatus is reduced owing to the delayed turnon of thetoilet heating apparatus.

In the toilet heating apparatus in accordance with the presentinvention, the temperature coefficient of resistance of the heat sourcemay be positive. In this case, the temperature of the energized heatsource asymptotically approaches a constant level because the resistanceof the heat source increases and the electric current flowing throughthe heat source decreases as the temperature of the heat sourceincreases. Thus, the toilet heating apparatus is prevented fromoverheating.

In the toilet heating apparatus in accordance with the presentinvention, the heat source controller can be adapted to variably controlthe electric power supply to the heat source. In this case, the toiletheating apparatus is prevented from overheating and also reliably heatedto an appropriate temperature even if the environmental conditions suchas room temperature, etc. have changed.

In the toilet heating apparatus in accordance with the presentinvention, the heat source controller can be adapted to vary theelectric power supply to the heat source stepwise. In this case, thetoilet heating apparatus is prevented from overheating.

In the toilet heating apparatus in accordance with the presentinvention, the heat source controller can be adapted to determine theelectric power supply to the heat source by feedback control. By this,the toilet heating apparatus is quickly heated to an appropriatetemperature and prevented from overheating.

In the toilet heating apparatus in accordance with the presentinvention, the heat source controller can be adapted to determine theelectric power supply to the heat source by learning control. By this,deviation from standard performance of the toilet heating apparatus atshipment can be corrected based on the performance at the firstoperation, so that the toilet heating apparatus can exhibit the expectedperformance from the second operation.

The toilet heating apparatus in accordance with the present inventionmay further comprise a seating detection apparatus which detects theseating of a person on the toilet seat, and the heat source controllermay be adapted to decrease the electric power supply to the heat sourcewhen the seating detection apparatus detects the seating of a person onthe toilet seat. This feature can be used in an arrangement in which,after a person sits on the toilet seat, the person's feet contact thetoilet heating mat placed near the toilet seat, buttocks contact theheating toilet seat and the back contacts the heating toilet seat coverto keep them warm. By this, the comfort of the toilet heating apparatusis not impaired even if the electric power supply to the toilet heatingapparatus is reduced after the person sits on the toilet seat. Thus, theelectric power consumption of the toilet heating apparatus is reduced byreducing the power supply to the toilet heating apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1(a) is a sectional view of a heat radiator in accordance with apreferred embodiment of the present invention. FIG. 1(b) is thesectional view of FIG. 1(a) along line A—A.

FIG. 2 is a plan view of the heat generating sheet of a heat radiator inaccordance with a preferred embodiment of the present invention.

FIG. 3 is a partially enlarged view of FIG. 2.

FIG. 4 is a diagram showing the heat emission from a heat generatingsheet.

FIG. 5 is a sectional view of a heat radiator in accordance with anotherpreferred embodiment of the present invention.

FIG. 6(a) is a sectional view of a heating apparatus in accordance witha preferred embodiment of the present invention. FIG. 6(b) is thesectional view of FIG. 6(a) along line A—A.

FIG. 7 is the top view of a heating apparatus in accordance with apreferred embodiment of the present invention which is embodied as aheating toilet seat.

FIGS. 8(a) and 8(b) are the sectional views of FIG. 7 along line A—A.

FIGS. 9(a) and 9(b) are sectional views of a heating apparatus inaccordance with a preferred embodiment of the present invention which isembodied as a heating toilet seat.

FIG. 10 is the top view of a heating apparatus in accordance with apreferred embodiment of the present invention which is embodied as aheating toilet seat.

FIG. 11 is the sectional view of FIG. 10 along line A—A.

FIG. 12 is a sectional view of a heating apparatus in accordance with apreferred embodiment of the present invention which is embodied as aheating toilet seat.

FIG. 13 is a sectional view of the heating apparatus of FIG. 12 showingthe fabrication process of the heating apparatus.

FIG. 14 is a sectional view of the heating apparatus of FIG. 12 andmolds showing the fabrication process of the heating apparatus.

FIG. 15 is a sectional view of the heating apparatus of FIG. 12 showinganother fabrication process of the heating apparatus.

FIG. 16 is a sectional view of the heating apparatus of FIG. 12 showinganother fabrication process of the heating apparatus.

FIG. 17 is a sectional view of a heating apparatus in accordance with apreferred embodiment of the present invention which is embodied as aheating toilet seat.

FIGS. 18(a) and 18(b) are sectional views of the heating apparatus ofFIG. 17 and molds showing the fabrication process of the heatingapparatus.

FIG. 19 is a sectional view of a heating apparatus in accordance with apreferred embodiment of the present invention which is embodied as aheating toilet seat.

FIGS. 20(a) and 20(b) are sectional views of the heating apparatus ofFIG. 19 and molds showing the fabrication process of the heatingapparatus.

FIG. 21 is a sectional view of a heating apparatus in accordance with apreferred embodiment of the present invention which is embodied as aheating toilet seat.

FIG. 22 is a sectional view of the heating apparatus of FIG. 21 andmolds showing the fabrication process of the heating apparatus.

FIG. 23 is a sectional view of a heating apparatus in accordance with apreferred embodiment of the present invention which is embodied as aheating toilet seat.

FIG. 24 is a sectional view of a heat generating sheet wrapped with aresin film.

FIG. 25 is a sectional view of a heating apparatus in accordance with apreferred embodiment of the present invention which is embodied as aheating toilet seat.

FIG. 26 is a sectional view of a heating apparatus in accordance with apreferred embodiment of the present invention which is embodied as aheating toilet seat.

FIG. 27 is a sectional view of a heating apparatus in accordance with apreferred embodiment of the present invention which is embodied as aheating toilet seat.

FIG. 28 is a bird's-eye view of a room wherein heating apparatuses inaccordance with preferred embodiments of the present invention areinstalled.

FIG. 29 is a bird's-eye view of a toilet wherein heating apparatuses inaccordance with preferred embodiments of the present invention areinstalled.

FIG. 30 is a sectional view of a toilet wherein heating apparatuses inaccordance with preferred embodiments of the present invention areinstalled.

FIG. 31 is a diagram showing the relation between the electric currentflowing through the heat generating sheet of a heating apparatus inaccordance with a preferred embodiment of the present invention and thetemperature of the heat generating sheet.

FIG. 32 is a diagram showing an example of a control sequence of theheating apparatus in accordance with a preferred embodiment of thepresent invention.

FIG. 33 is a block diagram showing an example of a control sequence ofthe heating apparatus in accordance with a preferred embodiment of thepresent invention.

FIG. 34 is a diagram showing an example of a control sequence of theheating apparatus in accordance with a preferred embodiment of thepresent invention.

FIG. 35 is a diagram showing an example of a control sequence of theheating apparatus in accordance with a preferred embodiment of thepresent invention.

THE BEST MODE FOR CARRYING OUT THE INVENTION

A heat radiator in accordance with a preferred embodiment of the presentinvention will be described.

As shown in FIGS. 1(a) and 1(b), a heat radiator 1 has a heat source ora heat generating sheet 2, an insulator 3 for covering the surface ofthe heat generating sheet 2 to be directed toward the human body, aninsulator 4 for covering the surface of the heat generating sheet 2 tobe directed away from the human body and a pair of electrodes 5. Thefree surface of the insulator 3 forms a surface for contacting with thehuman body.

The heat generating sheet 2 is energized to generate heat and emitinfrared radiation whose penetration depth into the human body is tonear warmth sensing points of the human body.

By warmth sensing points of the human body is meant a portion of theskin of the human body where thermal receptors for sensing warmth exist.The warmth sensing points of the human body are located 200 to 300 μmbelow the surface of the skin.

The infrared radiation entering the body is absorbed as it passesthrough the body. Any unabsorbed infrared radiation passes out of thebody. The transmittance τ of the infrared radiation is expressed by theformula τ=I₁/I₀, wherein I₀ is the incident energy and I₁ is thetransmission energy. The transmittance τ varies with the characteristicsand the thickness of the body. The relation between the transmittanceτthe infrared absorption coefficient μ of the body and the thickness xof the body is expressed by the formula τ=exp(−μ x). The infraredabsorption coefficient μ varies with the characteristics of the body andthe wavelength of the infrared. The penetration depth indexes whetherthe infrared radiation can pass through the body or not. The penetrationdepth is the travel distance of the infrared radiation into the bodybefore it damps to {fraction (1/10)}. In other words, the penetrationdepth is the thickness of the body resulting in a transmittance τ of 10%. The penetration depth varies with the characteristics of the body andthe wavelength of the infrared radiation. The penetration depth into thehuman body of infrared radiation with a wavelength of 2.5 to 50 μm is200 to 300 μm.

The thickness of the insulator 3 is made less than the penetration depthof the infrared radiation into the insulator 3. The penetration depth ofinfrared radiation with a wavelength of 3 to 12 μm into an insulator 3made of polypropylene is about 1.5 mm. The penetration depth of infraredradiation with a wavelength of 3 to 12 μm into an insulator 3 made ofacrylonitrile butadiene styrene is about 390 μm.

In the heat radiator 1, a predetermined voltage is applied between thepair of electrodes 5 to energize the heat generating sheet 2. Thus, theheat generating sheet 2 is heated and emits infrared radiation.

The heat generated by the heat generating sheet 2 passes to the freesurface of the insulator 3 through heat transfer and heat conduction.The thickness of the insulator 3 is less than the penetration depth ofthe infrared radiation into the insulator 3. As a result, the thicknessof the insulator 3 is small. Thus, the heat generated by the heatgenerating sheet 2 quickly passes to the free surface of the insulator3, thereby quickly heating the free surface of the insulator 3, whichforms the surface for contacting with the human body, to an appropriatetemperature.

Part of infrared radiation from the surface of the heat generating sheet2 directed toward the human body is absorbed by the insulator 3 andconverted to heat. The infrared radiation is absorbed and converted toheat at every depth point of the insulator 3 because the thickness ofthe insulator 3 is less than the penetration depth of the infraredradiation into the insulator 3. The heat converted from the infraredradiation passes to the free surface of the insulator 3 through heatconduction. The heat converted from the infrared radiation quicklypasses to the free surface of the insulator 3 because the infraredradiation is absorbed and converted to heat at every depth point of theinsulator 3 and the thickness of the insulator 3 is small. Thus, thefree surface of the insulator 3, which forms the surface for contactingwith the human body, is quickly heated to an appropriate temperature.

Part of infrared radiation from the heat generating sheet 2 passescompletely through the insulator 3 to the outside to be absorbed by thehuman body in contact with the free surface of the insulator 3 becausethe thickness of the insulator 3 is less than the penetration depth ofthe infrared radiation into the insulator 3. This infrared radiation iscompletely absorbed by the human body and converted to heat by the timeit reaches the vicinity of the warmth sensing points because thepenetration depth of the infrared radiation into the human body is tonear the warmth sensing points. Thus, the infrared radiation quicklyheats the vicinity of the warmth sensing points to an appropriatetemperature.

As is clear from the above description, the heat radiator 1 inaccordance with this preferred embodiment of the present invention canquickly heat the free surface of the insulator 3, which forms thesurface for contacting with the human body, to an appropriatetemperature and also directly and quickly heat the vicinity of thewarmth sensing points of the human body to an appropriate temperature.Thus, the heat radiator 1 in accordance with this preferred embodimentof the present invention has a high capability of quick heating. Thus, aheating apparatus into which the heat radiator 1 in accordance with thispreferred embodiment of the present invention is incorporated has a highcapability of quick heating.

The insulator 3 is preferably made of a polyester resin such aspolypropylene, polyethylene terephthalate, polybutylene terephthalate,polyethylene naphthalate, etc., or styrene resin such as acrylonitrilestyrene, acrylonitrile butadiene styrene, etc. These resins have highertransmittance of infrared radiation than other resins. Thus, the majorpart of the infrared radiation from the heat generating sheet 2 passesthrough the insulator 3 made of one of these resins to directly heat thehuman body. Thus, quick heating capability of the heat radiator 1 isfurther enhanced. Polyethylene terephthalate is highly effective toenhance the quick heating capability of the heat radiator 1 becausepolyethylene terephthalate has high transmittance of long-wave infraredradiation which is easily absorbed by the human body.

The heat generating sheet 2 preferably adheres closely to the insulator3. When the heat generating sheet 2 adheres closely to the insulator 3,the heat transfer coefficient between the heat generating sheet 2 andthe insulator 3 increases and the quick heating capability of the heatradiator 1 increases. Generally speaking, a heat generating sheet canadhere closely to the insulator covering it.

The heat generating sheet 2 is preferably porous. When the porous heatgenerating sheet 2 is bonded to the insulator 3, adhesive agentinfiltrates into the pores of the heat generating sheet 2. Thus, theporous heat generating sheet 2 adheres closely to the insulator 3. Whenthe porous heat generating sheet 2 is integrally molded with theinsulator 3, resin material forming the insulator 3 infiltrates into thepores of the heat generating sheet 2. Thus, the porous heat generatingsheet 2 adheres closely to the insulator 3. Thus, the quick heatingcapability of the heat radiator 1 increases.

As shown in FIGS. 2 and 3, the porous heat generating sheet 2 ispreferably a mixed paper of carbon fibers and natural pulp fibers. Theporous heat generating sheet 2 shown in FIGS. 2 and 3 is a mixed paperof carbon fibers 8 and natural pulp fibers 6. The mixed paper is made bya process comprising the steps of mixing natural pulp fibers 6 such ashemp pulp fibers, etc., binder 7 made of PVA resin, carbon fibers 8 andwater to make a pulp solution, pouring the pulp solution on a net tomake a wet sheet, mechanically drying the wet sheet with a roller tomake a dry sheet, and heating the dry sheet to fuse the binder 7,thereby bonding point contact portions between the carbon fibers 8 andpoint contact portions between the carbon fibers 8 and natural pulpfibers 6. The heat generating sheet 2 made of a mixed paper of carbonfibers 8 and natural pulp fibers 6 has stable resistance because thepoint contact portions between the carbon fibers 8 are stably maintainedby the binder 7. When voltage is applied between the pair of electrodes5 connected to the opposite ends of the heat generating sheet 2 made ofa mixed paper, electric current flows through the carbon fibers 8 toheat the carbon fibers 8 by Joule heat. The carbon fibers 8 thereforeemit infrared radiation. The mixed paper shown in FIGS. 2 and 3 contains25 weight % of 1 to 5 mm long carbon fibers, weighs 20.5 g/m², and isabout 200 μm thick. As shown in FIG. 3, void spaces 9 are formed aroundthe carbon fibers 8.

The carbon fibers 8 are efficient infrared radiators. The mixed paper ofthe carbon fibers 8 and the natural pulp fibers 6 is porous and canendure exposure to a high temperature fused resin. Thus, the heatgenerating sheet 2 made of a mixed paper of the carbon fibers 8 and thenatural pulp fibers 6 is suitable for integral molding with theinsulator 3 made of resin. The carbon fibers 8 are preferably surroundedby void spaces 9. The void spaces 9 form heat insulating layers. Thus,the temperature of the carbon fibers 8 surrounded by the void spaces 9quickly rises after the mixed paper is energized. Thus, the carbonfibers 8 quickly emit infrared radiation after the mixed paper isenergized. Thus, the quick heating capability of the heat radiator 1increases.

The void ratio of the mixed paper is preferably equal to or greater than60 volume %. When the void ratio of the mixed paper is equal to orgreater than 60 volume %, air layers or heat insulating layers arereliably formed around the carbon fibers 8. Thus, the temperatureincrease rate of the carbon fibers 8 increases and the time from thestart of the energizing of the mixed paper to the start of the emissionof the infrared radiation decreases. Thus, the quick heating capabilityof the heat radiator 1 increases.

It is preferable for a 200 μm thick mixed paper to have a weight equalto or less than 21 g/m² so as to have an apparent density equal to orless than 0.105 g/cm³. When the mixed paper has an apparent densitygreater than 0.15 g/cm³, the void ratio of the mixed paper decreases,the temperature increase rate of the carbon fibers 8 decreases, and thequick heating capability of the heat radiator 1 decreases. FIG. 4 showsa comparison of spectral emission corresponding to rated electric powerconsumption between a mixed paper with an apparent density of 0.11 g/cm³and a mixed paper with an apparent density of 0.5 g/Cm³. As is clearfrom FIG. 4, the spectral emission of the mixed paper with smallerapparent density is larger than that of the mixed paper with largerapparent density.

As shown in FIG. 5, the heat radiator 1 may be provided with an infraredreflector 10 facing the surface of the heat generating sheet 2 directedaway from the human body and a heat insulator 11 facing the infraredreflector 10. The infrared radiation from the surface of the heatgenerating sheet 2 directed away from the human body is reflected towardthe human body by the infrared reflector 10, thereby contributing totemperature increase of the human body. Thus, the quick heatingcapability of the heat radiator 1 increases. Transfer of heat generatedby the heat generating sheet 2 to the insulator 4 is blocked by the heatinsulator 11. Thus, the temperature increase rate of the insulator 3increases and the quick heating capability of the heat radiator 1increases.

A heating apparatus having the heat radiator 1 will be described.

As shown in FIGS. 6(a) and 6(b), a heating apparatus 12 comprises afront surface resin layer 13 to be directed toward the human body and arear surface resin layer 14. The front surface resin layer 13 forms theinsulator 3 of the heat radiator 1 covering the surface of the heatgenerating sheet 2 directed toward the human body. The front surfaceresin layer 13 and the rear surface resin layer 14 cooperate to sandwichthe heat generating sheet 2 of the heat radiator 1. A pair of electrodes5 are connected to the opposite ends of the heat generating sheet 2.

The thickness of the front surface resin layer 13 is less than thepenetration depth of the infrared radiation into the front surface resinlayer 13. Thus, the front surface resin layer 13 is thin and does nothave sufficient strength against external forces. However, the frontsurface resin layer 13 can be reinforced by the rear surface resin layer14 if the front surface resin layer 13 and the rear surface resin layer14 cooperate to sandwich the heat generating sheet 2. Thus, a heatingapparatus 12 which has a quick heating capability and sufficientstrength against external forces can be obtained.

The front surface resin layer 13 and the rear surface resin layer 14must be united into an integral body so as to reinforce the frontsurface resin layer 13 by the rear surface resin layer 14. The followingprocesses are preferable to unite them into an integral body.

(1) Process 1

As shown in FIGS. 7 and 8(b), a heating apparatus 12 a which is embodiedas a heating toilet seat comprises a front surface resin layer 13, arear surface resin layer 14 and a horseshoe-shaped heat generating sheet2. A pair of electrodes 5 are connected to the opposite ends of the heatgenerating sheet 2. Electric wires extend from the electrodes 5. Therear surface resin layer 14 is honeycombed. The front surface resinlayer 13 and the rear surface resin layer 14 cooperate to sandwich theheat generating sheet 2. The free surface of the front surface resinlayer 13 forms a surface for contacting with the human body. Projections13 a extending from the front surface resin layer 13 and penetrating theheat generating sheet 2 are inserted into penetration holes 14 a formedin the rear surface resin layer 14. The end portions of the projections13 a are then formed with swellings 13 b larger than the diameters ofthe penetration holes 14 a. The front surface resin layer 13 and therear surface resin layer 14 are mechanically united into an integralbody by the projections 13 a.

The heating apparatus 12 a is fabricated by the following process. Asshown in FIG. 8(a), the projections 13 a extending from the frontsurface resin layer 13 are inserted into penetration holes formed in theheat generating sheet 2. The heat generating sheet 2 is bonded to thefront surface resin layer 13. As shown in FIG. 8(b), the projections 13a are inserted into penetration holes 14 a formed in the rear surfaceresin layer 14. The end portions of the projections 13 a are heat fusedto form swellings 13 b.

In the process 1, the front surface resin layer 13 and the rear surfaceresin layer 14 are mechanically united. Thus, they can be reliablyunited into an integral body even if they are hard to bond together.

(2) Process 2

As shown in FIG. 9(b), a heating apparatus 12 b which is embodied as aheating toilet seat has the same structure as that of the heatingapparatus 12 a. However, the ends of the projections 13 a extending fromthe front surface resin layer 13 are provided beforehand with premoldedswellings 13 c.

The heating apparatus 12 b is fabricated by the following process. Asshown in FIG. 9(a), the projections 13 a extending from the frontsurface resin layer 13 are inserted into penetration holes formed in theheat generating sheet 2. The heat generating sheet 2 is bonded to thefront surface resin layer 13. As shown in FIG. 9(b), the projections 13a provided at their ends with the premolded swellings 13 c are insertedinto penetration holes 14 a formed in the rear surface resin layer 14.The swellings 13 c resiliently deform to penetrate the holes 14 a.

In the process 2, the front surface resin layer 13 and the rear surfaceresin layer 14 are mechanically united. Thus, they can be reliablyunited into an integral body even if they are hard to bond together.

(3) Process 3

As shown in FIGS. 10 and 11, a heating apparatus 12 c which is embodiedas a heating toilet seat comprises a front surface resin layer 13, arear surface resin layer 14 and a horseshoe-shaped heat generating sheet2. A pair of electrodes 5 are connected to the opposite ends of the heatgenerating sheet 2. Electric wires extend from the electrodes 5. Therear surface resin layer 14 is honeycombed. The front surface resinlayer 13 and the rear surface resin layer 14 cooperate to sandwich theheat generating sheet 2. The free surface of the front surface resinlayer 13 forms a surface for contacting with the human body. The innerperipheral portion and the outer peripheral portion of the heatingapparatus 12 c form abutting surfaces between the front surface resinlayer 13 and the rear surface resin layer 14. An electric wire 15 isdisposed at the abutting surfaces. The abutting surfaces between thefront surface resin layer 13 and the rear surface resin layer 14 nearthe electric wire 15 are fused to be bonded.

The heating apparatus 12 c is fabricated by the following process. Theelectric wire 15 is embedded beforehand to half its diameter in theabutting surface of the rear surface resin layer 14 or the front surfaceresin layer 13. The heat generating sheet 2 is bonded to the frontsurface resin layer 13. The heat generating sheet 2 is sandwiched by thefront surface resin layer 13 and the rear surface resin layer 14. Thefront surface resin layer 13 and the rear surface resin layer 14 areabutted together at the inner peripheral portion and the outerperipheral portion of the heating apparatus 12 c. A predeterminedvoltage is applied between a pair of terminals 16 formed at the oppositeends of the electric wire 15 to energize the electric wire 15 andthereby fuse and bond the abutting surfaces between the front surfaceresin layer 13 and the rear surface resin layer 14.

In the process 3, since the bonded surfaces can be easily re-fused byenergizing the electric wire 15, the front surface resin layer 13 can beremoved from the rear surface resin layer 14 to enable removal of theheat generating sheet 2 from the heating apparatus 12 c. Thus, reuse ofthe heat generating sheet 2 is expedited.

(4) Process 4

As shown in FIG. 12, in a heating apparatus 12 d which is embodied as aheating toilet seat, the front surface resin layer 13 and the rearsurface resin layer 14 are fused into an integral body.

The heating apparatus 12 d is fabricated by the following process. Asshown in FIG. 13, the heat generating sheet 2 is placed on the premoldedrear surface resin layer 14 to be bonded to the premolded rear surfaceresin layer 14. As shown in FIG. 14, the premolded rear surface resinlayer 14 carrying the heat generating sheet 2 is placed in the femalemold 16 a of a mold 16 for low pressure molding. Resin material 17 ofthe front surface resin layer 13 is poured into the female mold 16 a .The mold 16 is closed by the male mold 16 b . Low pressure molding iscarried out to form the heating apparatus 12 d.

In the process 4, unity between the front surface resin layer 13 and therear surface resin layer 14 increases and the strength of the heatingapparatus 12 d against external forces increases. Quick heatingcapability of the heating apparatus 12 d increases because adherence ofthe heat generating sheet 2 to the front resin layer 13 increases. Lowpressure molding protects the heat generating sheet 2 from damage duringthe molding operation.

It is possible to place the heat generating sheet 2 on the premoldedfront surface resin layer 13, bond the heat generating sheet 2 to thepremolded front surface resin layer 13, place the premolded frontsurface resin layer 13 carrying the heat generating sheet 2 in the malemold 16 b of the mold 16 for low pressure molding, pour the material 17of the rear surface resin layer 14 into the male mold 16 b , close themold 16 by the female mold 16 a , and carry out the low pressure moldingto form the heating apparatus 12 d. In this case, the mold 16 is usedupside down.

In the process 4, the premolded rear surface resin layer 14 may beprovided with projections 14 b for immobilizing the heat generatingsheet 2 as shown in FIG. 15. Thus, the heat generating sheet 2 is keptfrom sliding and crumpling during the molding operation. When the heatgenerating sheet 2 is placed on the premolded front surface layer 13,the front surface layer 13 may be provided with the same projections asprojections 14 b.

In the process 4, the premolded rear surface resin layer 14 may beprovided with irregularities or grooves 14 c in the surface receivingthe heat generating sheet 2 as shown in FIG. 16. Thus, the front surfaceresin layer 13 intrudes into the irregularities or grooves 14 c to befirmly united with the rear surface resin layer 14 as an integral body.Thus, the strength of the heating apparatus 12 d against external forcesincreases.

(5) Process 5

As shown in FIG. 17, a heating apparatus 12 e which is embodied as aheating toilet seat has a front surface resin layer 13, a heatgenerating sheet 2, a rear surface resin layer 14 which cooperates withthe front surface resin layer 13 to sandwich the heat generating sheet 2and a bottom cover 18. The rear surface resin layer 14 is honeycombed. Avoid space is formed between the rear surface resin layer 14 and thebottom cover 18.

The heating apparatus 12 e is fabricated by the following process. Asshown in FIG. 18(a), the front surface resin layer 13 is low pressuremolded by a mold 19 for low pressure molding comprising a male mold 19a, a middle mold 19 b and a female mold 19 c. The male mold 19 a isremoved. The front surface resin layer 13 is held in the female mold 19c. The front surface resin layer 13 is kept from shrinking and warpingby the middle mold 19 b. As shown in FIG. 18(b), the heat generatingsheet 2 is placed on and bonded to the front surface resin layer 13.Resin material of the rear surface resin layer 14 is poured into thefemale mold 19 c. The mold 19 is closed by a male mole 19 d. Lowpressure molding is carried out to mold the rear surface resin layer 14with the front surface resin layer 13, thereby uniting them into anintegral body. The molded body is removed from the mold 19. A premoldedbottom cover 18 is attached to the molded body.

In the process 5, the same effects as in the process 4 can be obtained.In the process 5, the front surface resin layer 13, the heat generatingsheet 2 and the rear surface resin layer 14 can be united into anintegral body by a continuous series of processes. Thus, the trouble oftransferring partially fabricated items such as the premolded frontsurface resin layer 13, the premolded rear surface resin layer 14, etc.,and placing them in the mold can be avoided. The void space between therear surface resin layer 14 and the bottom cover 18 is used as a wiringspace as well as contributes to lighten the heating apparatus 12 e.

It is possible to mold the rear surface resin layer 14 first and hold itin the mold, then mold the front surface resin layer 13 with the rearsurface resin layer 14, thereby uniting them into an integral body.

(6) Process 6

As shown in FIG. 19, a heating apparatus 12 f which is embodied as aheating toilet seat has a front surface resin layer 13, a heatgenerating sheet 2 and a rear surface resin layer 14 which cooperateswith the front surface resin layer 13 to sandwich the heat generatingsheet 2.

The heating apparatus 12 f is fabricated by the following process. Asshown in FIG. 20(a), a resin film 20 which forms the front surface resinlayer 13 is vacuum attracted to a female mold 21 a of a mold 21 for lowpressure molding. The heat generating sheet 2 is placed on and bonded tothe resin film 20. As shown in FIG. 20(b), resin material of the rearsurface resin layer 14 is poured into the female mold 21 a. The mold 21is closed by a male mold 21 b. Low pressure molding is carried out toform the heating apparatus 12 f.

In the process 6, the same effects as in the process 4 can be obtained.In the process 6, the distribution of the thickness of the front surfaceresin layer 13 can be made even and the the thickness of the frontsurface resin layer 13 can be made small. When the distribution of thethickness of the front surface resin layer 13 is even, the temperaturedistribution of the free surface of the front surface resin layer 13which forms the surface for contacting with the human body is even.Thus, the comfort of the heating apparatus 12 f is enhanced. When thethickness of the front surface resin layer 13 is small, the quantity ofinfrared radiation passing through the front surface resin layer 13increases and the quick heating capability of the heating apparatus 12 fincreases.

(7) Process 7

As shown in FIG. 21, a heating apparatus 12 g which is embodied as aheating toilet seat has a front surface resin layer 13, a heatgenerating sheet 2 and a rear surface resin layer 14 which cooperateswith the front surface resin layer 13 to sandwich the heat generatingsheet 2.

The heating apparatus 12 g is fabricated by the following process. Asshown in FIG. 22, the heat generating sheet 2 is placed on a female mold23 a of a mold 23 for low pressure molding. Resin material of the rearsurface resin layer 14 is poured into the female mold 23 a. The mold 23is closed by a male mold 23 b. Low pressure molding is carried out tomold the rear surface resin layer 14 with the heat generating sheet 2thereby uniting them into an integral body. The rear surface resin layer14 carrying the heat generating sheet 2 is placed in another mold forlow pressure molding. This mold is not shown in the FIG. 22. Resinmaterial of the front surface resin layer 13 is poured into the mold.Low pressure molding is carried out to form the heating apparatus 12 g.

In the process 7, unity between the front surface resin layer 13 and therear surface resin layer 14 increases and the strength of the heatingapparatus 12 g against external forces increases. The quick heatingcapability of the heating apparatus 12 g increases because adherence ofthe heat generating sheet 2 to the front resin layer 13 increases.

It is possible to mold the front surface resin layer 13 with the heatgenerating sheet 2 first, then mold the rear surface resin layer 14 withthe front surface resin layer 13, thereby uniting them into an integralbody.

In the process 7, the female mold 23 a may be provided with projections23 c for immobilizing the heat generating sheet 2 as shown in FIG. 22.Thus, the heat generating sheet 2 is kept from sliding and crumplingduring the molding operation.

In the heating apparatuses 12 a to 12 g, the heat generating sheet 2 maybe given the same color as the front surface resin layer 13. Thus, theheat generating sheet 2 cannot be seen through and users of the heatingapparatuses 12 a to 12 g do not feel uneasy even if the front surfaceresin layer 13 is light colored.

In the heating apparatuses 12 a to 12 g, the front surface resin layer13 and/or the rear surface resin layer 14 may be foamed resin layers asshown in FIG. 23. By this, the heating apparatuses 12 a to 12 g becomeflexible and the comfort of the heating apparatuses 12 a to 12 g isenhanced.

In the heating apparatuses 12 a to 12 g, the heat generating sheet 2 maybe wrapped with a resin film 25 beforehand as shown in FIG. 24. In thiscase, the heat generating sheet 2 is protected from damage when thefront surface resin layer 13, the heat generating sheet 2 and the rearsurface resin layer 14 are united into an integral body and themanufacturing efficiency of the heating apparatuses 12 a to 12 gincreases because handling of the heat generating sheet 2 becomes easy.

When the heat generating sheet 2 is wrapped with a resin film 25beforehand, the portion of the resin film 25 opposing the rear surfaceresin layer 14 may be an infrared reflection film 25 a as shown in FIG.24. In this case, the infrared radiation from the surface of thegenerating sheet 2 directed away from the human body is reflected towardthe human body by the infrared reflection film 25 a, therebycontributing to temperature increase of the human body. Thus, the quickheating capability of the heat radiators 12 a to 12 g increases.

In the heating apparatuses 12 a to 12 c, a cushioning layer 26 may besandwiched between the rear surface resin layer 14 and the heatgenerating sheet 2 as shown in FIG. 25. When the front surface resinlayer 13, the heat generating sheet 2 and the rear surface resin layer14 are united into an integral body by any one of the processes 1 to 3,there is a possibility of their not being sufficiently united into anintegral body because of size mismatch between the front surface resinlayer 13 and the rear surface resin layer 14 caused by manufacturingerror. However, if a cushioning layer 26 is sandwiched between the rearsurface resin layer 14 and the heat generating sheet 2, any sizemismatch between the front surface resin layer 13 and the rear surfaceresin layer 14 is absorbed by the cushioning layer 26. Thus, sufficientunity can be obtained.

When a cushioning layer 26 is sandwiched between the rear surface resinlayer 14 and the heat generating sheet 2 in the heating apparatuses 12 ato 12 c, the cushioning layer 26 may be integrally molded with the rearsurface resin layer 14. By this, the trouble of inserting the cushioninglayer 26 between the heat generating sheet 2 and the rear surface resinlayer 14 can be avoided when the front surface resin layer 13, the heatgenerating sheet 2 and the rear surface resin layer 14 are united intoan integral body. Thus, the manufacturing efficiency of the heatingapparatuses 12 a to 12 c increases.

When a cushioning layer 26 is sandwiched between the rear surface resinlayer 14 and the heat generating sheet 2 in the heating apparatuses 12 ato 12 c, the cushioning layer 26 may be a heat insulator. In this case,the heat generated by the heat generating sheet 2 is not absorbed by thecushioning layer 26, the heating efficiency of the heat generating sheet2 increases and the quick heating capability of the heating apparatuses12 a to 12 c increases.

As in the heating apparatuses 12 a to 12 c and 12 e, the rear surfaceresin layer 14 may be honeycombed. In this case, the weights of theheating apparatuses 12 a to 12 c and 12 e are reduced.

In the heating apparatuses 12 a to 12 c, the rear surface resin layer 14may be provided with a hollow 14 d wherein a heat sensor 27 is receivedas shown in FIG. 26. In this case, the heat generating sheet 2 can beprecisely controlled and the heating apparatuses 12 a to 12 c can beprecisely controlled.

If the temperature distribution of the heat generating sheet 2 is unevenin the heating apparatuses 12 a to 12 g, the front surface resin layer13 facing the higher temperature portion of the heat generating sheet 2may be made thick and the front surface resin layer 13 facing the lowertemperature portion of the heat generating sheet 2 may be made thin. Bythis, temperature distribution of the free surface of the front surfaceresin layer 13 which forms the surface for contacting with the humanbody becomes even and the comfort of the heating apparatuses 12 a to 12g is enhanced. In the example shown in FIG. 27, the portion of the frontsurface resin layer 13 facing the electrodes 5 is made thicker thanother portions taking into account that the temperature of theelectrodes 5 is higher than that of other portions. If thehorseshoe-shaped heat generating sheet 2 is used as shown in FIGS. 7 and10, the thickness of the front surface resin layer 13 may be graduallydecreased from the portion opposing the inner periphery of the heatgenerating sheet 2 to the portion opposing the outer periphery of theheat generating sheet 2 because the distance between the pair ofelectrodes 5 increases from the inner periphery to the outer peripheryand the temperature of the heat generating sheet 2 decreases from theinner periphery to the outer periphery. When the portion of the frontsurface resin layer 13 facing the higher temperature portion of the heatgenerating sheet 2 is made thick and the portion of the front surfaceresin layer 13 facing the lower temperature portion of the heatgenerating sheet 2 is made thin, the temperature distribution of thefree surface of the front surface resin layer 13 which forms the surfacefor contacting with the human body becomes even. Thus, the comfort ofthe heating apparatuses 12 a to 12 g is enhanced.

The heating apparatus 12 having the heat radiator 1 can be applied tovarious kinds of heating apparatuses such as room heating apparatuses,toilet heating apparatuses, etc. As shown in FIG. 28, examples of roomheating apparatuses include a floor heating panel 12 h, a wall heatingpanel 12 i, a heating carpet 12 j, a heating panel 12 k, etc. As shownin FIG. 29, examples of toilet heating apparatuses include a heatingtoilet mat 12 m, a heating panel 12 n, a heating toilet seat cover 12 p,a heating toilet seat 12 q, etc. The heating apparatus 12 in accordancewith the present invention wherein the heat generating sheet 2 isflexible and the front surface resin layer 13 and the rear surface resinlayer 14 are made of flexible material can be applied to a heating robe,winter clothes, a chair seat, a chair backrest, a chair armrest, etc.

A room heating apparatus such as the heating panel 12 h, the wallheating panel 12 i, the heating carpet 12 j, the heating panel 12 k,etc. shown in FIG. 28 may further comprise a human body detectingapparatus 28 such as an infrared sensor, pyroelectric sensor, Dopplersensor, microwave sensor, CO₂ sensor, microphone sensor, etc. which candetect the presence of a person in a room and a heat source controller29 which energizes the heat generating sheet 2 only when the human bodydetecting apparatus 28 detects the presence of a person. By this, theelectric power consumption of the room heating apparatus is reducedbecause the room heating apparatus operates only when a person ispresent in the room.

A toilet heating apparatus such as the heating toilet mat 12 m, theheating panel 12 n, the heating toilet seat cover 12 p, the heatingtoilet seat 12 q, etc. shown in FIG. 29 may further comprise a heatsource controller 31 a which energizes the heat generating sheet 2 inaccordance with a control signal from a control switch 30 disposedoutside the toilet. Thus, the toilet heating apparatus can be startedjust before a person enters the toilet and stopped just after the personleaves the toilet. Thus, the toilet can be comfortably used and theelectric power consumption of the toilet heating apparatus can bereduced.

A toilet heating apparatus such as the heating toilet mat 12 m, theheating panel 12 n, the heating toilet seat cover 12 p, the heatingtoilet seat 12 q, etc. shown in FIG. 29 may further comprise a heatsource controller 31 b which energizes the heat generating sheet 2 onlywhen an electric lamp 33 in the toilet is switched on by a controlswitch 32 disposed in or outside the toilet. In an ordinary home, theelectric lamp 33 in the toilet is switched on only when the toilet isused. Thus, the above described heat source controller 31 b enablescomfortable use of the toilet as well as reduction of electric powerconsumption of the toilet heating apparatus.

A toilet heating apparatus such as the heating toilet mat 12 m, theheating panel 12 n, the heating toilet seat cover 12 p, the heatingtoilet seat 12 q, etc. shown in FIG. 29 may further comprise a humanbody detecting apparatus 34 which can detect the presence of a person ina toilet and a heat source controller 31 c which energizes the heatgenerating sheet 2 only when the human body detecting apparatus 34detects the presence of a person. Thus, the electric power consumptionof the toilet heating apparatus is reduced because the toilet heatingapparatus operates only when a person is present in the toilet. The sameapparatus as the human body detecting apparatus 28 shown in FIG. 28 maybe used as the human body detecting apparatus 34. An apparatus fordetecting the seating of a person on a toilet seat used in a bidet maybe used as the human body detecting apparatus 34.

When the same apparatus as the human body detecting apparatus 28 shownin FIG. 28 is used as the human body detecting apparatus 34, the heatsource controller 31 c can be adapted to energize the heat generatingsheet 2 a predetermined time after the human body detecting apparatus 34detects a person. The human body detecting apparatus 34 detects a personjust after the person enters the toilet. Around 10 to 20 seconds passbetween the time a person enters the toilet and the time the person sitson the heating toilet seat 12 q. Thus, even if the heat sourcecontroller 31 c energizes the heat generating sheet 2 a predeterminedtime after the human body detecting apparatus 34 detects the presence ofa person, some time is still available between the time the heatgenerating sheet 2 is energized and the time the person sits on thetoilet heating seat 12 q. The surface of the toilet heating apparatusfor contacting with the human body can be reliably heated to anappropriate temperature during the available time because the toiletheating apparatus in accordance with the present invention is excellentin quick heating capability. A toilet heating apparatus such as theheating toilet mat 12 m, the heating panel 12 n, the heating toilet seatcover 12 p, the heating toilet seat 12 q, etc. achieves its warmingeffect by making contact with the person sitting on the heating toiletseat 12 q or by being present very close to the person sitting on theheating toilet seat 12 q. Thus, the comfort of the toilet heatingapparatus is not impaired so long as the temperature of the surface ofthe toilet heating apparatus for contacting with the human body israised to an appropriate level before the person sits on the heatingtoilet seat 12 q. Thus, the electric power consumption of the toiletheating apparatus is reduced without impairing the comfort of the toiletheating apparatus owing to the delayed turnon of the toilet heatingapparatus.

The heat source controller 31 c may energize the heat generating sheet 2at time T-t after the human body detecting apparatus 34 detects aperson. T is the time between detection of the person by the human bodydetecting apparatus 34 and the seating of the person on the heatingtoilet seat 12 q and t is the time from energizing of the heatgenerating sheet 2 to the completion of the temperature rise of thefront surface resin layer 13 to a predetermined level. The comfort ofthe toilet heating apparatus is not impaired because the temperature ofthe surface of the toilet heating apparatus for contacting with thehuman body rises to an appropriate level before the person sits on theheating toilet seat 12 q. Thus, the electric power consumption of thetoilet heating apparatus is reduced without impairing the comfort of thetoilet heating apparatus owing to the above-mentioned delayed turnon ofthe toilet heating apparatus.

The human body detecting apparatus 34 may be one capable of detectingthe distance between the human body detecting apparatus 34 and theperson that is mounted on a flushing water tank disposed adjacent to theheating toilet seat 12 q as shown in FIG. 30 and the heat sourcecontroller 31 c may be one that energizes the heat generating sheet 2when the distance between the human body detecting apparatus 34 and theperson becomes a predetermined value. An automatic focusing sensor usedfor a camera can be used for the human body detecting apparatus 34capable of detecting the distance to the person. Even if the toiletheating apparatus is turned on when the person reaches a point apredetermined distance from the heating toilet seat 12 q, thetemperature of the surface of the toilet heating apparatus forcontacting with the human body can nevertheless be raised to anappropriate level because the toilet heating apparatus having the heatradiator 1 is excellent in quick heating capability. The comfort of thetoilet heating apparatus is therefore not impaired. The electric powerconsumption of the toilet heating apparatus is reduced owing to thedelayed turnon of the toilet heating apparatus.

In a toilet heating apparatus such as the heating toilet mat 12 m, theheating panel 12 n, the heating toilet seat cover 12 p, the heatingtoilet seat 12 q, etc. shown in FIG. 29, the temperature coefficient ofresistance of the heat generating sheet 2 may be positive. When thetemperature coefficient of resistance of the heat generating sheet 2 ispositive, the temperature of the energized heat generating sheet 2asymptotically approaches a constant level as shown in FIG. 31, becausethe resistance of the heat generating sheet 2 increases and the electriccurrent flowing through the heat heat generating sheet 2 decreases asthe temperature of the heat generating sheet 2 increases. Thus, thetoilet heating apparatus is prevented from overheating. If the constanttemperature is set at a level near body temperature, the temperature ofthe surface of the toilet heating apparatus for contacting with thehuman body automatically rises to an appropriate level. A heatingelement made of the mixture of carbon particles and matrix resin has apositive temperature coefficient of resistance. When the heating elementis energized, the carbon particles generate heat and the temperature ofthe heating element rises. When the temperature of the heating elementrises, the matrix resin expands, the space between the carbon particlesincreases, the resistance of the heating element increases, the electriccurrent in the heating element decreases and the temperature of theheating element drops. When the temperature of the heating elementdrops, the matrix resin contracts, the space between the carbonparticles decreases, the resistance of the heating element decreases,the electric current in the heating element increases and thetemperature of the heating element rises. The above described phenomenonis repeated to hold the temperature of the heating element at a constantlevel. A metal resistor also has a positive temperature coefficient ofresistance.

In a toilet heating apparatus such as the heating toilet mat 12 m, theheating panel 12 n, the heating toilet seat cover 12 p, the heatingtoilet seat 12 q, etc. shown in FIG. 29, the heat source controller 31a, 31 b or 31 c can be adapted to variably control the electric powersupply to the heat generating sheet 2. In this case, the toilet heatingapparatus is prevented from overheating and also reliably heated to anappropriate temperature even if the environmental conditions such asroom temperature, etc. have changed.

In a toilet heating apparatus such as the heating toilet mat 12 m, theheating panel 12 n, the heating toilet seat cover 12 p, the heatingtoilet seat 12 q, etc. shown in FIG. 29, the heat source controller 31a, 31 b or 31 c can be adapted to vary the electric power supply to theheat generating sheet 2 stepwise as shown in FIG. 32. By this, theincrease rate of the temperature of the toilet heating apparatusincreases and the toilet heating apparatus is prevented fromoverheating.

In a toilet heating apparatus such as the heating toilet mat 12 m, theheating panel. 12 n, the heating toilet seat cover 12 p, the heatingtoilet seat 12 q, etc. shown in FIG. 29, the heat source controller 31a, 31 b or 31 c can be adapted to determine the electric power supply tothe heat generating sheet 2 by feedback control as shown in FIG. 33. InFIG. 33, the appropriate temperature of the surface of the toiletheating apparatus is the setting value, the present temperature of thesurface of the toilet heating apparatus is the control variable and thedifference between the setting value and the control variable is thedeviation. PID computing is carried out corresponding to the deviationto determine the operating variable or the electric power supply to theheat generating sheet 2. The determined electric power is supplied tothe controlled system or the heat generating sheet 2. Rapid fluctuationof ambient temperature, etc. affects the operating variable as thedisturbance. P computing varies the operating variable proportionally tothe deviation. I computing varies the operating variable proportionallyto the time integral of the deviation. D computing varies the operatingvariable proportionally to the time differential of the deviation. PIDcomputing combines these computings to determine the operating variable.PID computing enables quick and precise optimum control.

As shown in FIG. 34, D computing is omitted to achieve quick heatingwhen the deviation is large at the start of the control(line a in FIG.34). P computing is omitted to prevent overheating when the deviation issmall at the start of the control(line b in FIG. 34). Usually Dcomputing is omitted at the start of the control and started when thedeviation becomes small to achieve quick heating.

The initial electric power supply in the control shown in FIG. 32 or theinitial control constants in the control shown in FIG. 33 may bedetermined in accordance with the ambient temperature in the toilet.When the ambient temperature is low, the initial electric power supplyis increased or the initial control constants are increased to enhancethe quick heating capability of the toilet heating apparatus. When theambient temperature is high, the initial electric power supply isdecreased or the initial control constants are decreased to prevent thetoilet heating apparatus from overheating.

In a toilet heating apparatus such as the heating toilet mat 12 m, theheating panel 12 n, the heating toilet seat cover 12 p, the heatingtoilet seat 12 q, etc. shown in FIG. 29, the heat source controller 31a, 31 b or 31 c can be adapted to determine the electric power supply tothe heat generating sheet 2 by learning control. When the toilet heatingapparatus is shipped from the factory, constants of the control shown inFIG. 32 or 33 are set to raise the surface temperature of the toiletheating apparatus to a predetermined level in a predetermined time. Thesurface temperature of the toilet heating apparatus should rise to T₀,t₀ after the start of the control as shown by line a in FIG. 35. Becauseof the deviation from standard performance of the heat generating sheet2, deviation from standard thickness of the front surface resin layer13, etc., however, the surface temperature of the toilet heatingapparatus sometimes rises only to T₀-ΔT, t₀ after the start of thecontrol, as shown by line b in FIG. 35. In this case, the constants ofthe control are corrected corresponding to the deviation ΔT by means ofthe learning control to correct the electric power supply to the heatgenerating sheet 2. Thus, the toilet heating apparatus can exhibit theexpected performance from the next operation.

A toilet heating apparatus such as the heating toilet mat 12 m, theheating panel 12 n, the heating toilet seat cover 12 p, the heatingtoilet seat 12 q, etc. shown in FIG. 29, can be provided with adetecting apparatus 35 which detects the seating of a person on theheating toilet seat 12 q, and the heat source controller 31 a, 31 b or31 c can be adapted to decrease the electric power supply to the heatgenerating sheet 2 when the detecting apparatus 35 detects the seatingof a person on the heating toilet seat 12 q. A load cell can be used asthe detecting apparatus 35. This feature can be used in an arrangementin which, after a person sits on the heating toilet seat 12 q, theperson's feet contact the toilet heating mat 12 m placed near theheating toilet seat 12 q, buttocks contact the heating toilet seat 12 qand the back contacts the heating toilet seat cover 12 p to keep themwarm. The heating panel 12 n can also be located to be very close to theperson to be warmed. By this, the comfort of the toilet heatingapparatus is not impaired even if the electric power supply to thetoilet heating apparatus is reduced after the person sits on the heatingtoilet seat 12 q. Thus, the electric power consumption of the toiletheating apparatus is reduced by reducing of the power supply to thetoilet heating apparatus.

INDUSTRIAL APPLICABILITY OF THE INVENTION

The present invention provides a heating apparatus which has a surfacefor contacting with the human body and is excellent in quick heatingcapability.

What is claimed is:
 1. A heat radiator for emitting infrared radiationto the human body, comprising: a heat source energized to emit infraredradiation, whose penetration depth into the human body is to near warmthsensing points of the human body; and an insulator covering the surfaceof the heat source directed toward the human body; wherein the freesurface of the insulator forms a surface for contacting with the humanbody and the thickness of the insulator is less than the penetrationdepth of the infrared radiation into the insulator.
 2. A heat radiatorof claim 1, wherein the insulator is made of polyester resin or styreneresin.
 3. A heat radiator of claim 1, wherein the insulator adheresclosely to the heat source.
 4. A heat radiator of claim 3, wherein theheat source is a porous heat generating sheet.
 5. A heat radiator ofclaim 4, wherein the porous heat generating sheet is a mixed paper ofcarbon fibers and natural pulp fibers, and the carbon fibers aresurrounded by void spaces.
 6. A heat radiator of claim 5, wherein thevoid ratio of the mixed paper is equal to or greater than 60 volume %.7. A heat radiator of claim 1, further comprising an infrared reflectorfacing the surface of the heat source directed away from the human body.8. A heating apparatus having a heat radiator of any of claims 1 to 7,comprising: a front surface resin layer to be directed toward the humanbody; and a rear surface resin layer; wherein the front surface resinlayer forms the insulator of the heat radiator covering the surface ofthe heat source directed toward the human body, and the front surfaceresin layer and the rear surface resin layer cooperate to sandwich theheat source of the heat radiator.
 9. A heating apparatus of claim 8,wherein the front surface resin layer, the heat source and the rearsurface resin layer are united into an integral body by the processcomprising the steps of: inserting projections extending from the frontsurface resin layer and penetrating through the heat source intopenetration holes formed in the rear surface resin layer; and heatfusing the end portions of the projections to form swellings.
 10. Aheating apparatus of claim 8, wherein the front surface resin layer, theheat source and the rear surface resin layer are united into an integralbody by the process of inserting projections extending from the frontsurface resin layer, penetrating through the heat source and beingprovided with swellings at their ends into penetration holes formed inthe rear surface resin layer.
 11. A heating apparatus of claim 8,wherein the front surface resin layer, the heat source and the rearsurface resin layer are united into an integral body by the processcomprising the steps of: abutting the front surface resin layer againstthe rear surface resin layer; and energizing an electric wire embeddedbeforehand in the abutting surface of the rear surface resin layer orthe front surface resin layer to fuse and bond the abutting surfaces.12. A heating apparatus of claim 8, wherein the front surface resinlayer, the heat source and the rear surface resin layer are united intoan integral body by the process comprising the steps of: placing theheat source on the premolded front surface resin layer or the premoldedrear surface resin layer; placing the premolded front surface resinlayer carrying the heat source or the premolded rear surface resin layercarrying the heat source in a mold for low pressure molding; pouringresin material of the rear surface resin layer or the front surfaceresin layer into the mold; and closing the mold to carry out lowpressure molding.
 13. A heating apparatus of claim 12, wherein thepremolded front surface resin layer or the premolded rear surface resinlayer is provided with projections for immobilizing the heat source. 14.A heating apparatus of claim 12, wherein the premolded rear surfaceresin layer is provided with irregularities or grooves in the surfacereceiving the heat source.
 15. A heating apparatus of claim 8, whereinthe front surface resin layer, the heat source and the rear surfaceresin layer are united into an integral body by the process comprisingthe steps of: molding the front surface resin layer or the rear surfaceresin layer; holding the molded front surface resin layer or the moldedrear surface resin layer in the mold; placing the heat source on thefront surface resin layer or the rear surface resin layer; pouring resinmaterial of the rear surface resin layer or the front surface resinlayer into the mold; and closing the mold to carry out low pressuremolding.
 16. A heating apparatus of claim 8, wherein the front surfaceresin layer, the heat source and the rear surface resin layer are unitedinto an integral body by the process comprising the steps of: vacuumattracting a resin film to a mold for low pressure molding; placing theheat source on the resin film; pouring resin material of the rearsurface resin layer into the mold; and closing the mold to carry out lowpressure molding.
 17. A heating apparatus of claim 8, wherein the frontsurface resin layer, the heat source and the rear surface resin layerare united into an integral body by the process comprising the steps of:placing the heat source on a first mold for low pressure molding;pouring resin material of the front surface resin layer or the rearsurface resin layer into the mold; closing the mold to carry out lowpressure molding to unite the front surface resin layer or the rearsurface resin layer and the heat source into an integral body; placingthe front surface resin layer united with the heat source or the rearsurface resin layer united with the heat source in a second mold for lowpressure molding; pouring resin material of the rear surface resin layeror the front surface resin layer into the mold; and closing the mold tocarry out low pressure molding.
 18. A heating apparatus of claim 17,wherein the first mold for low pressure molding is provided withprojections for immobilizing the heat source.
 19. A heating apparatus ofclaim 8, wherein the heat source is given the same color as the frontsurface resin layer.
 20. A heating apparatus of claim 8, wherein thefront surface resin layer and/or the rear surface resin layer are foamedresin layers.
 21. A heating apparatus of claim 8, wherein the heatsource is wrapped with a resin film beforehand.
 22. A heating apparatusof claim 21, wherein the portion of the resin film opposing the rearsurface resin layer is an infrared reflector.
 23. A heating apparatus ofany of claims 9 to 11, wherein a cushioning layer is sandwiched betweenthe rear surface resin layer and the heat source.
 24. A heatingapparatus of claim 23, wherein the cushioning layer is integrally moldedwith the rear surface resin layer.
 25. A heating apparatus of claim 23or 24, wherein the cushioning layer is a heat insulator.
 26. A heatingapparatus of claim 8, wherein the rear surface resin layer ishoneycombed.
 27. A heating apparatus of claim 8, wherein the rearsurface resin layer is provided with a hollow wherein a heat sensor isreceived.
 28. A heating apparatus of claim 8, wherein the front surfaceresin layer facing a higher temperature portion of the heat source ismade thick and the front surface resin layer facing a lower temperatureportion of the heat source is made thin.
 29. A room heating apparatus ofany of claims 8 to 28, further comprising: a human body detecting meansfor detecting presence of a person in a room; and a heat source controlmeans for energizing the heat source only when the human body detectingmeans detects presence of a person.
 30. A toilet heating apparatus ofany of claims 8 to 28, further comprising a heat source control meansfor energizing the heat source in accordance with a control signal fromoutside a toilet.
 31. A toilet heating apparatus of any of claims 8 to28, further comprising a heat source control means for energizing theheat source only when an electric lamp in the toilet is switched on. 32.A toilet heating apparatus of any of claims 8 to 28, further comprising:a human body detecting means for detecting presence of a person in atoilet; and a heat source control means for energizing the heat sourceonly when the human body detecting means detects presence of a person.33. A toilet heating apparatus of claim 32, wherein the heat sourcecontrol means energizes the heat source a predetermined time after thehuman body detecting means detects presence of a person.
 34. A toiletheating apparatus of claim 32, wherein the heat source control meansenergizes the heat source at time T-t after the human body detectingmeans detects presence of a person, where T is time between detection ofpresence of a person by the human body detecting means and seating ofthe person on a toilet seat, and t is time from energizing of the heatsource to completion of temperature rise of the front surface resinlayer to a predetermined level.
 35. A toilet heating apparatus of claim32, wherein the human body detecting means can detect distance betweenthe human body detecting means and the person, and the heat sourcecontrol means energizes the heat source when the distance between thehuman body detecting means and the person becomes a predetermined value.36. A toilet heating apparatus of any of claims 30 to 35, whereintemperature coefficient of resistance of the heat source is positive.37. A toilet heating apparatus of any of claims 30 to 35, wherein theheat source control means variably controls the electric power supply tothe heat source.
 38. A toilet heating apparatus of claim 37, wherein theheat source control means varies the electric power supply to the heatsource stepwise.
 39. A toilet heating apparatus of claim 37, wherein theheat source control means determines the electric power supply to theheat source by feedback control.
 40. A toilet heating apparatus of claim37, wherein the heat source control means determines the electric powersupply to the heat source by learning control.
 41. A toilet heatingapparatus of any of claims 30 to 40, further comprising a seatingdetection means for detecting seating of a person on a toilet seat,wherein the heat source control means decreases the electric powersupply to the heat source when the seating detection means detectsseating of a person on the toilet seat.